Display screen or portion thereof with transitional graphical user interface



FIG. 1 is a front view of a first image in a sequence according to the first embodiment our design for a display screen or portion thereof with transitional graphical user interface;

FIG. 2 is a front view of a second image in the sequence thereof;

FIG. 3 is a front view of a third image in the sequence thereof;

FIG. 4 is a front view of a fourth image in the sequence thereof;

FIG. 5 is a front view of a fifth image in the sequence thereof;

FIG. 6 is a front view of a first image in a sequence showing the design of FIG. 1 in a different environment;

FIG. 7 is a front view of a second image in the sequence showing the design of FIG. 2 in a different environment;

FIG. 8 is a front view of a third image in the sequence showing the design of FIG. 3 in a different environment;

FIG. 9 is a front view of a fourth image in the sequence showing the design of FIG. 4 in a different environment; and,

FIG. 10 is a front view of a fifth image in the sequence showing the design of FIG. 5 in a different environment.

The appearance of the claimed design transitions between the images shown in FIGS. 1 through 5, and the images shown in FIGS. 6 through 10, respectively. The process or period in which one image transitions to another forms no part of the claimed design.

The outermost broken line rounded rectangle showing an electronic device illustrates environmental subject matter. The broken line showing a display screen, and all other broken lines showing portions of the graphical user interface illustrate portions of the article. None of the aforementioned broken line subject matter forms part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with transitional graphical user interface, as shown and described. 